Linux Kernel ALSA Caiaq Input Device Use-After-Free on Probe Failure
CVE-2026-98837 Published on October 18, 2026
ALSA: caiaq: unregister the input device when probe fails
In the Linux kernel, the following vulnerability has been resolved:
ALSA: caiaq: unregister the input device when probe fails
setup_card() registers the input device, whose name and phys point into
struct snd_usb_caiaqdev, and then goes on to snd_card_register() and
snd_usb_caiaq_control_init(). If either fails, snd_probe() calls
snd_card_free(), which frees the device state but leaves the input
device registered: card_free() only clears the pointer, and the input
device is unregistered from snd_disconnect() alone. Reading its "uevent"
attribute afterwards dereferences freed memory:
BUG: KASAN: slab-use-after-free in string+0x4a9/0x4f0
Read of size 1 at addr ffff8880208f5043 by task caiaq/4967
add_uevent_var+0x183/0x3a0
input_dev_uevent+0x162/0x900
dev_uevent+0x2f1/0x870
uevent_show+0x1ca/0x3a0
...
Unregister the input device on the probe error path, as
snd_disconnect() does. snd_usb_caiaq_input_disconnect() is a no-op when
no input device was registered.
Reproduced with a raw-gadget Audio Kontrol 1 and a temporary hack that
makes snd_usb_caiaq_control_init() fail.
Products Associated with CVE-2026-98837
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Affected Versions
Linux:- Version 6251e3e256337a30160ef59ab1580dde4d1acd28 and below 850810c12686f80cdf7530f4f21e0157d904f739 is affected.
- Version e59ecd4ee3a450db6cb4e4ecaa3efdd593f80056 and below 84727facd8506140cd04f2b0a8b1c4ddeac41cea is affected.
- Version 28abd224db4a49560b452115bca3672a20e45b2f and below 2e5a413cc2a489c9427ecd3d73ad764bfb0c7103 is affected.
- Version 28abd224db4a49560b452115bca3672a20e45b2f and below 0b7bd20f6379bc5e431fd74d866390f5b5b63f3c is affected.
- Version da938aa9fc7826901921dcea225948ab21a97e45 is affected.
- Version 09616e25f502080ba684fc7fcf959d1376ab756d is affected.
- Version b956e48371f2ff72b76be9a829800ecec963bd45 is affected.
- Version f537e3ad69609f6924a4db6b4a7f6561f5288bdd is affected.
- Version 096dd8519cf2f768e9e14f224b627f7aaee1a9c5 is affected.
- Version 6.12.86 and below 6.12.113 is affected.
- Version 6.18.27 and below 6.18.56 is affected.
- Version 5.10.258 and below 5.11 is affected.
- Version 5.15.209 and below 5.16 is affected.
- Version 6.1.175 and below 6.2 is affected.
- Version 6.6.140 and below 6.7 is affected.
- Version 7.0.4 and below 7.1 is affected.
- Version 7.1 is affected.
- Before 7.1 is unaffected.
- Version 6.12.113, <= 6.12.* is unaffected.
- Version 6.18.56, <= 6.18.* is unaffected.
- Version 7.2.10, <= 7.2.* is unaffected.
- Version 7.3-rc6, <= * is unaffected.